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<p>Compares the arguments.
</p>
<table class="wikitable" style="font-size:85%;">

<tr>
<th rowspan="2"> Operator name
</th>
<th rowspan="2"> Syntax
</th>
<th rowspan="2"> Over​load​able
</th>
<th colspan="2"> Prototype examples (for <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw1">class</span> T</span></span>)
</th>
</tr>
<tr>
<th> Inside class definition
</th>
<th> Outside class definition
</th>
</tr>
<tr>
<td> equal to
</td>
<td> <code>a == b</code>
</td>
<td style="background: #90ff90; color: black; vertical-align: middle; text-align: center;" class="table-yes">Yes
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span> T<span class="sy4">::</span><span class="me2">operator</span> <span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> T2 <span class="sy3">&amp;</span>b<span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span></span></span>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span> operator <span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> T <span class="sy3">&amp;</span>a, <span class="kw4">const</span> T2 <span class="sy3">&amp;</span>b<span class="br0">)</span><span class="sy4">;</span></span></span>
</td>
</tr>
<tr>
<td> not equal to
</td>
<td> <code>a != b</code>
</td>
<td style="background: #90ff90; color: black; vertical-align: middle; text-align: center;" class="table-yes">Yes
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span> T<span class="sy4">::</span><span class="me2">operator</span> <span class="sy3">!</span><span class="sy1">=</span><span class="br0">(</span><span class="kw4">const</span> T2 <span class="sy3">&amp;</span>b<span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span></span></span>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span> operator <span class="sy3">!</span><span class="sy1">=</span><span class="br0">(</span><span class="kw4">const</span> T <span class="sy3">&amp;</span>a, <span class="kw4">const</span> T2 <span class="sy3">&amp;</span>b<span class="br0">)</span><span class="sy4">;</span></span></span>
</td>
</tr>
<tr>
<td> less than
</td>
<td> <code>a &lt; b</code>
</td>
<td style="background: #90ff90; color: black; vertical-align: middle; text-align: center;" class="table-yes">Yes
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span> T<span class="sy4">::</span><span class="me2">operator</span> <span class="sy1">&lt;</span><span class="br0">(</span><span class="kw4">const</span> T2 <span class="sy3">&amp;</span>b<span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span></span></span>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span> operator <span class="sy1">&lt;</span><span class="br0">(</span><span class="kw4">const</span> T <span class="sy3">&amp;</span>a, <span class="kw4">const</span> T2 <span class="sy3">&amp;</span>b<span class="br0">)</span><span class="sy4">;</span></span></span>
</td>
</tr>
<tr>
<td> greater than
</td>
<td> <code>a &gt; b</code>
</td>
<td style="background: #90ff90; color: black; vertical-align: middle; text-align: center;" class="table-yes">Yes
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span> T<span class="sy4">::</span><span class="me2">operator</span> <span class="sy1">&gt;</span><span class="br0">(</span><span class="kw4">const</span> T2 <span class="sy3">&amp;</span>b<span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span></span></span>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span> operator <span class="sy1">&gt;</span><span class="br0">(</span><span class="kw4">const</span> T <span class="sy3">&amp;</span>a, <span class="kw4">const</span> T2 <span class="sy3">&amp;</span>b<span class="br0">)</span><span class="sy4">;</span></span></span>
</td>
</tr>
<tr>
<td> less than or equal to
</td>
<td> <code>a &lt;= b</code>
</td>
<td style="background: #90ff90; color: black; vertical-align: middle; text-align: center;" class="table-yes">Yes
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span> T<span class="sy4">::</span><span class="me2">operator</span> <span class="sy1">&lt;=</span><span class="br0">(</span><span class="kw4">const</span> T2 <span class="sy3">&amp;</span>b<span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span></span></span>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span> operator <span class="sy1">&lt;=</span><span class="br0">(</span><span class="kw4">const</span> T <span class="sy3">&amp;</span>a, <span class="kw4">const</span> T2 <span class="sy3">&amp;</span>b<span class="br0">)</span><span class="sy4">;</span></span></span>
</td>
</tr>
<tr>
<td> greater than or equal to
</td>
<td> <code>a &gt;= b</code>
</td>
<td style="background: #90ff90; color: black; vertical-align: middle; text-align: center;" class="table-yes">Yes
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span> T<span class="sy4">::</span><span class="me2">operator</span> <span class="sy1">&gt;=</span><span class="br0">(</span><span class="kw4">const</span> T2 <span class="sy3">&amp;</span>b<span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span></span></span>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span> operator <span class="sy1">&gt;=</span><span class="br0">(</span><span class="kw4">const</span> T <span class="sy3">&amp;</span>a, <span class="kw4">const</span> T2 <span class="sy3">&amp;</span>b<span class="br0">)</span><span class="sy4">;</span></span></span>
</td>
</tr>
<tr>
<td colspan="5">
<dl><dd>
<b>Notes</b><br>
</dd></dl>
<ul>
<li> All built-in operators return <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span></span></span>, and most user-defined overloads also return <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span></span></span> so that the user-defined operators can be used in the same manner as the built-ins. However, in a user-defined operator overload, any type can be used as return type (including <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">void</span></span></span>).
</li>
<li> <code>T2</code> can be any type including <code>T</code>
</li>
</ul>
</td>
</tr>
</table>
<table id="toc" class="toc"><tr><td>
<div id="toctitle"><h2>Contents</h2></div>
<ul>
<li class="toclevel-1 tocsection-1">
<a href="operator_comparison.html%23Explanation"><span class="tocnumber">1</span> <span class="toctext">Explanation</span></a>
<ul>
<li class="toclevel-2 tocsection-2"><a href="operator_comparison.html%23Arithmetic_comparison_operators"><span class="tocnumber">1.1</span> <span class="toctext">Arithmetic comparison operators</span></a></li>
</ul>
</li>
<li class="toclevel-1 tocsection-3">
<a href="operator_comparison.html%23Example"><span class="tocnumber">2</span> <span class="toctext">Example</span></a>
<ul>
<li class="toclevel-2 tocsection-4"><a href="operator_comparison.html%23Pointer_comparison_operators"><span class="tocnumber">2.1</span> <span class="toctext">Pointer comparison operators</span></a></li>
</ul>
</li>
<li class="toclevel-1 tocsection-5"><a href="operator_comparison.html%23Example_2"><span class="tocnumber">3</span> <span class="toctext">Example</span></a></li>
<li class="toclevel-1 tocsection-6"><a href="operator_comparison.html%23Notes"><span class="tocnumber">4</span> <span class="toctext">Notes</span></a></li>
<li class="toclevel-1 tocsection-7"><a href="operator_comparison.html%23Standard_library"><span class="tocnumber">5</span> <span class="toctext">Standard library</span></a></li>
<li class="toclevel-1 tocsection-8"><a href="operator_comparison.html%23See_also"><span class="tocnumber">6</span> <span class="toctext">See also</span></a></li>
</ul>
</td></tr></table>
<h3>
<span class="editsection">[<a href="http%3A//en.cppreference.com/mwiki/index.php" title="Edit section: Explanation">edit</a>]</span> <span class="mw-headline" id="Explanation">Explanation</span>
</h3>
<p>Returns the boolean result of comparison of the values of the arguments, which are not modified.
</p>
<h4>
<span class="editsection">[<a href="http%3A//en.cppreference.com/mwiki/index.php" title="Edit section: Arithmetic comparison operators">edit</a>]</span> <span class="mw-headline" id="Arithmetic_comparison_operators">Arithmetic comparison operators</span>
</h4>
<p>For every pair of promoted arithmetic types <code>L</code> and <code>R</code>, including enumeration types, the following function signatures participate in overload resolution:
</p>
<table class="t-dcl-begin"><tbody>
<tr class="t-dcl-sep">
<td></td>
<td></td>
<td></td>
</tr>
<tr class="t-dcl">
<td class="t-dcl-nopad"> <div><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span> operator<span class="sy1">&lt;</span><span class="br0">(</span>L, R<span class="br0">)</span><span class="sy4">;</span></span></div>
</td>
<td class="t-dcl-nopad">  </td>
<td class="t-dcl-nopad">  </td>
</tr>
<tr class="t-dcl-sep">
<td></td>
<td></td>
<td></td>
</tr>
<tr class="t-dcl">
<td class="t-dcl-nopad"> <div><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span> operator<span class="sy1">&gt;</span><span class="br0">(</span>L, R<span class="br0">)</span><span class="sy4">;</span></span></div>
</td>
<td class="t-dcl-nopad">  </td>
<td class="t-dcl-nopad">  </td>
</tr>
<tr class="t-dcl-sep">
<td></td>
<td></td>
<td></td>
</tr>
<tr class="t-dcl">
<td class="t-dcl-nopad"> <div><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span> operator<span class="sy1">&lt;=</span><span class="br0">(</span>L, R<span class="br0">)</span><span class="sy4">;</span></span></div>
</td>
<td class="t-dcl-nopad">  </td>
<td class="t-dcl-nopad">  </td>
</tr>
<tr class="t-dcl-sep">
<td></td>
<td></td>
<td></td>
</tr>
<tr class="t-dcl">
<td class="t-dcl-nopad"> <div><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span> operator<span class="sy1">&gt;=</span><span class="br0">(</span>L, R<span class="br0">)</span><span class="sy4">;</span></span></div>
</td>
<td class="t-dcl-nopad">  </td>
<td class="t-dcl-nopad">  </td>
</tr>
<tr class="t-dcl-sep">
<td></td>
<td></td>
<td></td>
</tr>
<tr class="t-dcl">
<td class="t-dcl-nopad"> <div><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span>L, R<span class="br0">)</span><span class="sy4">;</span></span></div>
</td>
<td class="t-dcl-nopad">  </td>
<td class="t-dcl-nopad">  </td>
</tr>
<tr class="t-dcl-sep">
<td></td>
<td></td>
<td></td>
</tr>
<tr class="t-dcl">
<td class="t-dcl-nopad"> <div><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span> operator<span class="sy3">!</span><span class="sy1">=</span><span class="br0">(</span>L, R<span class="br0">)</span><span class="sy4">;</span></span></div>
</td>
<td class="t-dcl-nopad">  </td>
<td class="t-dcl-nopad">  </td>
</tr>
<tr class="t-dcl-sep">
<td></td>
<td></td>
<td></td>
</tr>
</tbody></table>
<p>If the operands has arithmetic or enumeration type (scoped or unscoped), <i>usual arithmetic conversions</i> are performed following the rules for <a href="operator_arithmetic.html" title="cpp/language/operator arithmetic">arithmetic operators</a>. The values are compared after conversions:
</p>
<h3>
<span class="editsection">[<a href="http%3A//en.cppreference.com/mwiki/index.php" title="Edit section: Example">edit</a>]</span> <span class="mw-headline" id="Example">Example</span>
</h3>
<div class="t-example">
<div class="t-example-live-link"><div class="coliru-btn coliru-btn-run-init">Run this code</div></div>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="co2">#include &lt;iostream&gt;</span>
<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span>
<span class="br0">{</span>
    <a href="../io/basic_ostream.html"><span class="kw1439">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <a href="../io/manip/boolalpha.html"><span class="kw1445">std::<span class="me2">boolalpha</span></span></a><span class="sy4">;</span>
    <span class="kw4">int</span> n <span class="sy1">=</span> <span class="sy2">-</span><span class="nu0">1</span><span class="sy4">;</span>
 
    <span class="kw4">int</span> n2 <span class="sy1">=</span> <span class="nu0">1</span><span class="sy4">;</span>
    <a href="../io/basic_ostream.html"><span class="kw1439">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">" -1 == 1? "</span> <span class="sy1">&lt;&lt;</span> <span class="br0">(</span>n <span class="sy1">==</span> n2<span class="br0">)</span> <span class="sy1">&lt;&lt;</span> <span class="st0">'<span class="es1">\n</span>'</span>
              <span class="sy1">&lt;&lt;</span> <span class="st0">"Comparing two signed values:<span class="es1">\n</span>"</span>
              <span class="sy1">&lt;&lt;</span> <span class="st0">" -1  &lt; 1? "</span> <span class="sy1">&lt;&lt;</span> <span class="br0">(</span>n <span class="sy1">&lt;</span> n2<span class="br0">)</span> <span class="sy1">&lt;&lt;</span> <span class="st0">'<span class="es1">\n</span>'</span>
              <span class="sy1">&lt;&lt;</span> <span class="st0">" -1  &gt; 1? "</span> <span class="sy1">&lt;&lt;</span> <span class="br0">(</span>n <span class="sy1">&gt;</span> n2<span class="br0">)</span> <span class="sy1">&lt;&lt;</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
 
    <span class="kw4">unsigned</span> <span class="kw4">int</span> u <span class="sy1">=</span> <span class="nu0">1</span><span class="sy4">;</span>
    <a href="../io/basic_ostream.html"><span class="kw1439">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">"Comparing signed and unsigned:<span class="es1">\n</span>"</span>
              <span class="sy1">&lt;&lt;</span> <span class="st0">" -1  &lt; 1? "</span> <span class="sy1">&lt;&lt;</span> <span class="br0">(</span>n <span class="sy1">&lt;</span> u<span class="br0">)</span> <span class="sy1">&lt;&lt;</span> <span class="st0">'<span class="es1">\n</span>'</span>
              <span class="sy1">&lt;&lt;</span> <span class="st0">" -1  &gt; 1? "</span> <span class="sy1">&lt;&lt;</span> <span class="br0">(</span>n <span class="sy1">&gt;</span> u<span class="br0">)</span> <span class="sy1">&lt;&lt;</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
 
    <span class="kw4">unsigned</span> <span class="kw4">char</span> uc <span class="sy1">=</span> <span class="nu0">1</span><span class="sy4">;</span>
    <a href="../io/basic_ostream.html"><span class="kw1439">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">"Comparing signed and smaller unsigned:<span class="es1">\n</span>"</span>
              <span class="sy1">&lt;&lt;</span> <span class="st0">" -1  &lt; 1? "</span> <span class="sy1">&lt;&lt;</span> <span class="br0">(</span>n <span class="sy1">&lt;</span> uc<span class="br0">)</span> <span class="sy1">&lt;&lt;</span> <span class="st0">'<span class="es1">\n</span>'</span>
              <span class="sy1">&lt;&lt;</span> <span class="st0">" -1  &gt; 1? "</span> <span class="sy1">&lt;&lt;</span> <span class="br0">(</span>n <span class="sy1">&gt;</span> uc<span class="br0">)</span> <span class="sy1">&lt;&lt;</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<p>Output:
</p>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="text source-text"><pre class="de1">-1 == 1? false
Comparing two signed values:
 -1  &lt; 1? true
 -1  &gt; 1? false
Comparing signed and unsigned:
 -1  &lt; 1? false
 -1  &gt; 1? true
Comparing signed and smaller unsigned:
 -1  &lt; 1? true
 -1  &gt; 1? false</pre></div></div> 
</div>
<h4>
<span class="editsection">[<a href="http%3A//en.cppreference.com/mwiki/index.php" title="Edit section: Pointer comparison operators">edit</a>]</span> <span class="mw-headline" id="Pointer_comparison_operators">Pointer comparison operators</span>
</h4>
<p>For every type <code>P</code> which is either pointer to object or pointer to function or <span class="t-lc"><a href="../types/nullptr_t.html" title="cpp/types/nullptr t">std::nullptr_t</a></span>, and for every type <code>MP</code> that is a pointer to member object or pointer to member function, the following function signatures participate in overload resolution:
</p>
<table class="t-dcl-begin"><tbody>
<tr class="t-dcl-sep">
<td></td>
<td></td>
<td></td>
</tr>
<tr class="t-dcl">
<td class="t-dcl-nopad"> <div><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span> operator<span class="sy1">&lt;</span><span class="br0">(</span>P, P<span class="br0">)</span><span class="sy4">;</span></span></div>
</td>
<td class="t-dcl-nopad">  </td>
<td class="t-dcl-nopad">  </td>
</tr>
<tr class="t-dcl-sep">
<td></td>
<td></td>
<td></td>
</tr>
<tr class="t-dcl">
<td class="t-dcl-nopad"> <div><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span> operator<span class="sy1">&gt;</span><span class="br0">(</span>P, P<span class="br0">)</span><span class="sy4">;</span></span></div>
</td>
<td class="t-dcl-nopad">  </td>
<td class="t-dcl-nopad">  </td>
</tr>
<tr class="t-dcl-sep">
<td></td>
<td></td>
<td></td>
</tr>
<tr class="t-dcl">
<td class="t-dcl-nopad"> <div><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span> operator<span class="sy1">&lt;=</span><span class="br0">(</span>P, P<span class="br0">)</span><span class="sy4">;</span></span></div>
</td>
<td class="t-dcl-nopad">  </td>
<td class="t-dcl-nopad">  </td>
</tr>
<tr class="t-dcl-sep">
<td></td>
<td></td>
<td></td>
</tr>
<tr class="t-dcl">
<td class="t-dcl-nopad"> <div><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span> operator<span class="sy1">&gt;=</span><span class="br0">(</span>P, P<span class="br0">)</span><span class="sy4">;</span></span></div>
</td>
<td class="t-dcl-nopad">  </td>
<td class="t-dcl-nopad">  </td>
</tr>
<tr class="t-dcl-sep">
<td></td>
<td></td>
<td></td>
</tr>
<tr class="t-dcl">
<td class="t-dcl-nopad"> <div><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span>P, P<span class="br0">)</span><span class="sy4">;</span></span></div>
</td>
<td class="t-dcl-nopad">  </td>
<td class="t-dcl-nopad">  </td>
</tr>
<tr class="t-dcl-sep">
<td></td>
<td></td>
<td></td>
</tr>
<tr class="t-dcl">
<td class="t-dcl-nopad"> <div><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span> operator<span class="sy3">!</span><span class="sy1">=</span><span class="br0">(</span>P, P<span class="br0">)</span><span class="sy4">;</span></span></div>
</td>
<td class="t-dcl-nopad">  </td>
<td class="t-dcl-nopad">  </td>
</tr>
<tr class="t-dcl-sep">
<td></td>
<td></td>
<td></td>
</tr>
<tr class="t-dcl">
<td class="t-dcl-nopad"> <div><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span>MP, MP<span class="br0">)</span><span class="sy4">;</span></span></div>
</td>
<td class="t-dcl-nopad">  </td>
<td class="t-dcl-nopad">  </td>
</tr>
<tr class="t-dcl-sep">
<td></td>
<td></td>
<td></td>
</tr>
<tr class="t-dcl">
<td class="t-dcl-nopad"> <div><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span> operator<span class="sy3">!</span><span class="sy1">=</span><span class="br0">(</span>MP, MP<span class="br0">)</span><span class="sy4">;</span></span></div>
</td>
<td class="t-dcl-nopad">  </td>
<td class="t-dcl-nopad">  </td>
</tr>
<tr class="t-dcl-sep">
<td></td>
<td></td>
<td></td>
</tr>
</tbody></table>
<table class="metadata plainlinks ambox mbox-small-left ambox-notice" style=""><tr>
<td class="mbox-empty-cell"></td>
<td class="mbox-text" style="">This section is incomplete<br>Reason: n3498 needs to be applied </td>
</tr></table>
<p>Comparison operators can be used to compare two pointers (or pointers-to-members, for <span class="t-c"><span class="mw-geshi cpp source-cpp">operator<span class="sy1">==</span></span></span> and <span class="t-c"><span class="mw-geshi cpp source-cpp">operator<span class="sy3">!</span><span class="sy1">=</span></span></span> only), or a pointer and a null pointer constant, or two null pointer constants (but only as long as at least one of them is <span class="t-lc"><a href="../types/nullptr_t.html" title="cpp/types/nullptr t">std::nullptr_t</a></span>: comparison of NULL and NULL follows arithmetic comparison rules). <a href="implicit_cast.html" title="cpp/language/implicit cast">Pointer conversions</a> (pointer to member conversions if the arguments are pointers to members) and <a href="implicit_cast.html" title="cpp/language/implicit cast">qualification conversions</a> are applied to both operands to obtain the <i>composite pointer type</i>, as follows
</p>
<div class="t-li1">
<span class="t-li">1)</span> If both operands are null pointer constants, the composite pointer type is <span class="t-lc"><a href="../types/nullptr_t.html" title="cpp/types/nullptr t">std::nullptr_t</a></span>
</div>
<div class="t-li1">
<span class="t-li">2)</span> If one operand a null pointer constant and the other is a pointer, the composite type is exactly the pointer type</div>
<div class="t-li1">
<span class="t-li">3)</span> If both operands are pointers to the same type, with different cv-qualification, the composite is pointer to the same type with cv-qualification that is a union of the cv-qualifications of the arguments.
Note that this implies that any pointer can be compared with <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">void</span><span class="sy2">*</span></span></span>.</div>
<p>Results of comparing two pointers (after conversions) are determined as follows:
</p>
<div class="t-li1">
<span class="t-li">1)</span> If the pointers <code>p</code> and <code>q</code> </div>
<div class="t-li2">
<span class="t-li">a)</span> point to the same object or function</div>
<div class="t-li2">
<span class="t-li">b)</span> or point one past the end of the same array</div>
<div class="t-li2">
<span class="t-li">c)</span> or are both null pointers</div>
<dl><dd>then the pointers <i>compare equal</i>: <span class="t-c"><span class="mw-geshi cpp source-cpp">p<span class="sy1">==</span>q</span></span>, <span class="t-c"><span class="mw-geshi cpp source-cpp">p<span class="sy1">&lt;=</span>q</span></span>, and <span class="t-c"><span class="mw-geshi cpp source-cpp">p<span class="sy1">&gt;=</span>q</span></span> return <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw2">true</span></span></span>, while <span class="t-c"><span class="mw-geshi cpp source-cpp">p<span class="sy3">!</span><span class="sy1">=</span>q</span></span>, <span class="t-c"><span class="mw-geshi cpp source-cpp">p<span class="sy1">&lt;</span>q</span></span>, and <span class="t-c"><span class="mw-geshi cpp source-cpp">p<span class="sy1">&gt;</span>q</span></span> return <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw2">false</span></span></span>,
</dd></dl>
<div class="t-li1">
<span class="t-li">2)</span> If one of the operands is a null pointer and the other is not, they compare unequal: <span class="t-c"><span class="mw-geshi cpp source-cpp">p<span class="sy1">==</span>q</span></span> returns <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw2">true</span></span></span>, <span class="t-c"><span class="mw-geshi cpp source-cpp">p<span class="sy3">!</span><span class="sy1">=</span>q</span></span> returns <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw2">false</span></span></span>, the behavior of other operators is unspecified.</div>
<div class="t-li1">
<span class="t-li">3)</span> If the pointers <code>p</code> and <code>q</code> point to members of the same array <span class="t-c"><span class="mw-geshi cpp source-cpp">a<span class="br0">[</span>i<span class="br0">]</span></span></span> and <span class="t-c"><span class="mw-geshi cpp source-cpp">a<span class="br0">[</span>j<span class="br0">]</span></span></span> or one past the end of the array, they results of comparing the pointers is the same as the result of comparing the indexes: if <span class="t-c"><span class="mw-geshi cpp source-cpp">i<span class="sy1">&lt;</span>j<span class="sy1">==</span><span class="kw2">true</span></span></span> then <span class="t-c"><span class="mw-geshi cpp source-cpp">p<span class="sy1">&lt;</span>q <span class="sy1">==</span> <span class="kw2">true</span></span></span>.</div>
<div class="t-li1">
<span class="t-li">4)</span> If the pointers <code>p</code> and <code>q</code> point to non-static data members within the same class or different base subobjects within the same derived class, or to their members or subobjects, recursively, and if the pointed-to members/subobjects have the same access control (e.g. both <code>public:</code>), and the class is not a union, then the pointer to the later declared subobject/member compares greater than the pointer to the earlier declared subobject/member. In other words, class members in each of the three access  modes are positioned in memory in order of declaration.</div>
<div class="t-li1">
<span class="t-li">6)</span> If the pointers <code>p</code> and <code>q</code> point to members of the same <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw1">union</span></span></span>, they compare equal (typically an explicit conversion to <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">void</span><span class="sy2">*</span></span></span> is required for one of the operands)</div>
<div class="t-li1">
<span class="t-li">7)</span> If one of the pointers is a pointer to <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">void</span></span></span> and both pointers point to the same address or are both null pointers, they compare equal.</div>
<div class="t-li1">
<span class="t-li">8)</span> If two null pointer constants are compared, they compare equal.</div>
<div class="t-li1">
<span class="t-li">9)</span> If both operands are pointers to member (object or function), they compare equal if they both point to the same member of the most derived class.</div>
<div class="t-li1">
<span class="t-li">10)</span> Otherwise (if the pointers point to objects in different arrays, or to different functions, or to members of some object with different access control, etc), the results of <span class="t-c"><span class="mw-geshi cpp source-cpp">p<span class="sy1">&lt;</span>q</span></span>, <span class="t-c"><span class="mw-geshi cpp source-cpp">p<span class="sy1">&gt;</span>q</span></span>, <span class="t-c"><span class="mw-geshi cpp source-cpp">p<span class="sy1">&lt;=</span>q</span></span>, and <span class="t-c"><span class="mw-geshi cpp source-cpp">p<span class="sy1">&gt;=</span>q</span></span> are unspecified, and <span class="t-c"><span class="mw-geshi cpp source-cpp">p<span class="sy3">!</span><span class="sy1">=</span>q</span></span> returns <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw2">false</span></span></span>.</div>
<h3>
<span class="editsection">[<a href="http%3A//en.cppreference.com/mwiki/index.php" title="Edit section: Example">edit</a>]</span> <span class="mw-headline" id="Example_2">Example</span>
</h3>
<div class="t-example">
<div class="t-example-live-link"><div class="coliru-btn coliru-btn-run-init">Run this code</div></div>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="co2">#include &lt;iostream&gt;</span>
<span class="kw1">struct</span> Foo  <span class="br0">{</span> <span class="kw4">int</span> n1<span class="sy4">;</span> <span class="kw4">int</span> n2<span class="sy4">;</span> <span class="br0">}</span><span class="sy4">;</span>
<span class="kw1">union</span> Union <span class="br0">{</span> <span class="kw4">int</span> n<span class="sy4">;</span> <span class="kw4">double</span> d<span class="sy4">;</span> <span class="br0">}</span><span class="sy4">;</span>
<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span>
<span class="br0">{</span>
    <a href="../io/basic_ostream.html"><span class="kw1439">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <a href="../io/manip/boolalpha.html"><span class="kw1445">std::<span class="me2">boolalpha</span></span></a><span class="sy4">;</span>
 
    <span class="kw4">char</span> a<span class="br0">[</span><span class="nu0">4</span><span class="br0">]</span> <span class="sy1">=</span> <span class="st0">"abc"</span><span class="sy4">;</span>
 
    <span class="kw4">char</span><span class="sy2">*</span> p1 <span class="sy1">=</span> <span class="sy3">&amp;</span>a<span class="br0">[</span><span class="nu0">1</span><span class="br0">]</span><span class="sy4">;</span>
    <span class="kw4">char</span><span class="sy2">*</span> p2 <span class="sy1">=</span> <span class="sy3">&amp;</span>a<span class="br0">[</span><span class="nu0">2</span><span class="br0">]</span><span class="sy4">;</span>
    <a href="../io/basic_ostream.html"><span class="kw1439">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">"Pointers to array elements: p1 == p2 "</span> <span class="sy1">&lt;&lt;</span> <span class="br0">(</span>p1 <span class="sy1">==</span> p2<span class="br0">)</span>
              <span class="sy1">&lt;&lt;</span> <span class="st0">", p1 &lt; p2 "</span>  <span class="sy1">&lt;&lt;</span> <span class="br0">(</span>p1 <span class="sy1">&lt;</span> p2<span class="br0">)</span> <span class="sy1">&lt;&lt;</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
 
    Foo f<span class="sy4">;</span>
    <span class="kw4">int</span><span class="sy2">*</span> p3 <span class="sy1">=</span> <span class="sy3">&amp;</span>f.<span class="me1">n1</span><span class="sy4">;</span>
    <span class="kw4">int</span><span class="sy2">*</span> p4 <span class="sy1">=</span> <span class="sy3">&amp;</span>f.<span class="me1">n2</span><span class="sy4">;</span>
    <a href="../io/basic_ostream.html"><span class="kw1439">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">"Pointers to members of a class: p3 == p4 "</span> <span class="sy1">&lt;&lt;</span> <span class="br0">(</span>p3 <span class="sy1">==</span> p4<span class="br0">)</span>
              <span class="sy1">&lt;&lt;</span> <span class="st0">", p3 &lt; p4 "</span>  <span class="sy1">&lt;&lt;</span> <span class="br0">(</span>p3 <span class="sy1">&lt;</span> p4<span class="br0">)</span> <span class="sy1">&lt;&lt;</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
 
    Union u<span class="sy4">;</span>
    <span class="kw4">int</span><span class="sy2">*</span> p5 <span class="sy1">=</span> <span class="sy3">&amp;</span>u.<span class="me1">n</span><span class="sy4">;</span>
    <span class="kw4">double</span><span class="sy2">*</span> p6 <span class="sy1">=</span> <span class="sy3">&amp;</span>u.<span class="me1">d</span><span class="sy4">;</span>
    <a href="../io/basic_ostream.html"><span class="kw1439">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">"Pointers to members of a union: p5 == (void*)p6 "</span> <span class="sy1">&lt;&lt;</span> <span class="br0">(</span>p5 <span class="sy1">==</span> <span class="br0">(</span><span class="kw4">void</span><span class="sy2">*</span><span class="br0">)</span>p6<span class="br0">)</span>
              <span class="sy1">&lt;&lt;</span> <span class="st0">", p5 &lt; p6 "</span>  <span class="sy1">&lt;&lt;</span> <span class="br0">(</span>p5 <span class="sy1">&lt;</span> <span class="br0">(</span><span class="kw4">void</span><span class="sy2">*</span><span class="br0">)</span>p6<span class="br0">)</span> <span class="sy1">&lt;&lt;</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<p>Output:
</p>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="text source-text"><pre class="de1">Pointers to array elements: p1 == p2 false, p1 &lt; p2 true
Pointers to members of a class: p3 == p4 false, p3 &lt; p4 true
Pointers to members of a union: p5 == (void*)p6 true, p5 &lt; p6 false</pre></div></div> 
</div>
<h3>
<span class="editsection">[<a href="http%3A//en.cppreference.com/mwiki/index.php" title="Edit section: Notes">edit</a>]</span> <span class="mw-headline" id="Notes">Notes</span>
</h3>
<p>Because these operators group left-to-right, the expression <span class="t-c"><span class="mw-geshi cpp source-cpp">a<span class="sy1">&lt;</span>b<span class="sy1">&lt;</span>c</span></span> is parsed <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="br0">(</span>a<span class="sy1">&lt;</span>b<span class="br0">)</span><span class="sy1">&lt;</span>c</span></span>, and not <span class="t-c"><span class="mw-geshi cpp source-cpp">a<span class="sy1">&lt;</span><span class="br0">(</span>b<span class="sy1">&lt;</span>c<span class="br0">)</span></span></span> or <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="br0">(</span>a<span class="sy1">&lt;</span>b<span class="br0">)</span><span class="sy3">&amp;&amp;</span><span class="br0">(</span>b<span class="sy1">&lt;</span>c<span class="br0">)</span></span></span>.
</p>
<p>A common requirement for user-defined <code>operator&lt;</code> is <a href="http%3A//en.wikipedia.com/wiki/Strict_weak_ordering" class="extiw" title="enwiki:Strict weak ordering">strict weak ordering</a>. In particular, this is required by the standard algorithms and containers that work with <a href="../concept/Compare.html" title="cpp/concept/Compare"><code>Compare</code></a> types: <span class="t-lc"><a href="../algorithm/sort.html" title="cpp/algorithm/sort">std::sort</a></span>, <span class="t-lc"><a href="../algorithm/max_element.html" title="cpp/algorithm/max element">std::max_element</a></span>, <span class="t-lc"><a href="../container/map.html" title="cpp/container/map">std::map</a></span>, etc.
</p>
<p>Although the results of comparing pointers of random origin (e.g. not all pointing to members of the same array) is unspecified, many implementations provide <a href="http%3A//en.wikipedia.com/wiki/Total_order%23Strict_total_order" class="extiw" title="enwiki:Total order">strict total ordering</a> of pointers, e.g. if they are implemented as addresses within continuous virtual address space. Those implementations that do not (e.g. where not all bits of the pointer are part of a memory address and have to be ignored for comparison, or an additional calculation is required or otherwise pointer and integer is not a 1 to 1 relationship), provide a specialization of <span class="t-lc"><a href="../utility/functional/less.html" title="cpp/utility/functional/less">std::less</a></span> for pointers that has that guarantee. This makes it possible to use all pointers of random origin as keys in standard associative containers such as <span class="t-lc"><a href="../container/set.html" title="cpp/container/set">std::set</a></span> or <span class="t-lc"><a href="../container/map.html" title="cpp/container/map">std::map</a></span>.
</p>
<table class="metadata plainlinks ambox mbox-small-left ambox-notice" style=""><tr>
<td class="mbox-empty-cell"></td>
<td class="mbox-text" style="">This section is incomplete<br>Reason: equivalence vs. equality </td>
</tr></table>
<h3>
<span class="editsection">[<a href="http%3A//en.cppreference.com/mwiki/index.php" title="Edit section: Standard library">edit</a>]</span> <span class="mw-headline" id="Standard_library">Standard library</span>
</h3>
<p>Comparison operators are overloaded for many classes in the standard library.
</p>
<table class="t-dsc-begin">

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../types/type_info/operator_cmp.html" title="cpp/types/type info/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span></span></a></div></div>
</td>
<td>   checks whether the objects refer to the same type  <br> <span class="t-mark">(public member function of <code>std::type_info</code>)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../error/error_code/operator_cmp.html" title="cpp/error/error code/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span><span>operator&lt;</span></span></a></div></div>
</td>
<td>   compares two <code>error_code</code>s <br> <span class="t-mark">(function)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../error/error_condition/operator_cmp.html" title="cpp/error/error condition/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span><span>operator&lt;</span></span></a></div></div>
</td>
<td>   compares error_conditions and error_codes <br> <span class="t-mark">(function)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../utility/pair/operator_cmp.html" title="cpp/utility/pair/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span><span>operator&lt;</span><span>operator&lt;=</span><span>operator&gt;</span><span>operator&gt;=</span></span></a></div></div>
</td>
<td>   lexicographically compares the values in the pair  <br> <span class="t-mark">(function template)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../utility/tuple/operator_cmp.html" title="cpp/utility/tuple/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span><span>operator&lt;</span><span>operator&lt;=</span><span>operator&gt;</span><span>operator&gt;=</span></span></a></div></div>
</td>
<td>   lexicographically compares the values in the tuple  <br> <span class="t-mark">(function template)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../utility/bitset/operator_cmp.html" title="cpp/utility/bitset/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span></span></a></div></div>
</td>
<td>   compares the contents <br> <span class="t-mark">(public member function of <code>std::bitset</code>)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../memory/allocator/operator_cmp.html" title="cpp/memory/allocator/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span></span></a></div></div>
</td>
<td>  compares two allocator instances <br> <span class="t-mark">(public member function of <code>std::allocator</code>)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../memory/unique_ptr/operator_cmp.html" title="cpp/memory/unique ptr/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span><span>operator&lt;</span><span>operator&lt;=</span><span>operator&gt;</span><span>operator&gt;=</span></span></a></div></div>
</td>
<td>   compares to another <code>unique_ptr</code> or with <span class="t-c"><span class="mw-geshi cpp source-cpp">nullptr</span></span>  <br> <span class="t-mark">(function template)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../memory/shared_ptr/operator_cmp.html" title="cpp/memory/shared ptr/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span><span>operator&lt;</span><span>operator&lt;=</span><span>operator&gt;</span><span>operator&gt;=</span></span></a></div></div>
</td>
<td>   compares with another <code>shared_ptr</code> or with <span class="t-c"><span class="mw-geshi cpp source-cpp">nullptr</span></span>  <br> <span class="t-mark">(function template)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../utility/functional/function/operator_cmp.html" title="cpp/utility/functional/function/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span></span></a></div></div>
</td>
<td>   compares an <span class="t-lc"><a href="../utility/functional/function.html" title="cpp/utility/functional/function">std::function</a></span> with <span class="t-c"><span class="mw-geshi cpp source-cpp">std<span class="sy4">::</span><span class="me2">nullptr</span></span></span> <br> <span class="t-mark">(function template)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../chrono/duration/operator_cmp.html" title="cpp/chrono/duration/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span><span>operator&lt;</span><span>operator&lt;=</span><span>operator&gt;</span><span>operator&gt;=</span></span></a></div></div>
</td>
<td>   compares two durations <br> <span class="t-mark">(function template)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../chrono/time_point/operator_cmp.html" title="cpp/chrono/time point/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span><span>operator&lt;</span><span>operator&lt;=</span><span>operator&gt;</span><span>operator&gt;=</span></span></a></div></div>
</td>
<td>   compares two time points <br> <span class="t-mark">(function template)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../memory/scoped_allocator_adaptor/operator_cmp.html" title="cpp/memory/scoped allocator adaptor/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span></span></a></div></div>
</td>
<td>  compares two scoped_allocator_adaptor instances <br> <span class="t-mark">(public member function of <code>std::scoped_allocator_adaptor</code>)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../types/type_index/operator_cmp.html" title="cpp/types/type index/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span><span>operator&lt;</span><span>operator&lt;=</span><span>operator&gt;</span><span>operator&gt;=</span></span></a></div></div>
</td>
<td>   compares the underlying <span class="t-lc"><a href="../types/type_info.html" title="cpp/types/type info">std::type_info</a></span> objects <br> <span class="t-mark">(public member function of <code>std::type_index</code>)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../string/basic_string/operator_cmp.html" title="cpp/string/basic string/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span><span>operator&lt;</span><span>operator&gt;</span><span>operator&lt;=</span><span>operator&gt;=</span></span></a></div></div>
</td>
<td>   lexicographically compares two strings  <br> <span class="t-mark">(function template)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../locale/locale/operator_cmp.html" title="cpp/locale/locale/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span></span></a></div></div>
</td>
<td>   equality comparison between locale objects  <br> <span class="t-mark">(public member function of <code>std::locale</code>)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../container/array/operator_cmp.html" title="cpp/container/array/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span><span>operator&lt;</span><span>operator&lt;=</span><span>operator&gt;</span><span>operator&gt;=</span></span></a></div></div>
</td>
<td>   lexicographically compares the values in the array  <br> <span class="t-mark">(function template)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../container/deque/operator_cmp.html" title="cpp/container/deque/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span><span>operator&lt;</span><span>operator&lt;=</span><span>operator&gt;</span><span>operator&gt;=</span></span></a></div></div>
</td>
<td>   lexicographically compares the values in the deque  <br> <span class="t-mark">(function template)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../container/forward_list/operator_cmp.html" title="cpp/container/forward list/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span><span>operator&lt;</span><span>operator&lt;=</span><span>operator&gt;</span><span>operator&gt;=</span></span></a></div></div>
</td>
<td>   lexicographically compares the values in the forward_list  <br> <span class="t-mark">(function template)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../container/list/operator_cmp.html" title="cpp/container/list/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span><span>operator&lt;</span><span>operator&lt;=</span><span>operator&gt;</span><span>operator&gt;=</span></span></a></div></div>
</td>
<td>   lexicographically compares the values in the list  <br> <span class="t-mark">(function template)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../container/vector/operator_cmp.html" title="cpp/container/vector/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span><span>operator&lt;</span><span>operator&lt;=</span><span>operator&gt;</span><span>operator&gt;=</span></span></a></div></div>
</td>
<td>   lexicographically compares the values in the vector  <br> <span class="t-mark">(function template)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../container/map/operator_cmp.html" title="cpp/container/map/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span><span>operator&lt;</span><span>operator&lt;=</span><span>operator&gt;</span><span>operator&gt;=</span></span></a></div></div>
</td>
<td>   lexicographically compares the values in the map  <br> <span class="t-mark">(function template)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../container/multimap/operator_cmp.html" title="cpp/container/multimap/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span><span>operator&lt;</span><span>operator&lt;=</span><span>operator&gt;</span><span>operator&gt;=</span></span></a></div></div>
</td>
<td>   lexicographically compares the values in the multimap  <br> <span class="t-mark">(function template)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../container/set/operator_cmp.html" title="cpp/container/set/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span><span>operator&lt;</span><span>operator&lt;=</span><span>operator&gt;</span><span>operator&gt;=</span></span></a></div></div>
</td>
<td>   lexicographically compares the values in the set  <br> <span class="t-mark">(function template)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../container/multiset/operator_cmp.html" title="cpp/container/multiset/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span><span>operator&lt;</span><span>operator&lt;=</span><span>operator&gt;</span><span>operator&gt;=</span></span></a></div></div>
</td>
<td>   lexicographically compares the values in the multiset  <br> <span class="t-mark">(function template)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../container/unordered_map/operator_cmp.html" title="cpp/container/unordered map/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span></span></a></div></div>
</td>
<td>   compares the values in the unordered_map  <br> <span class="t-mark">(function template)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../container/unordered_multimap/operator_cmp.html" title="cpp/container/unordered multimap/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span></span></a></div></div>
</td>
<td>   compares the values in the unordered_multimap  <br> <span class="t-mark">(function template)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../container/unordered_set/operator_cmp.html" title="cpp/container/unordered set/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span></span></a></div></div>
</td>
<td>   compares the values in the unordered_set  <br> <span class="t-mark">(function template)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../container/unordered_multiset/operator_cmp.html" title="cpp/container/unordered multiset/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span></span></a></div></div>
</td>
<td>   compares the values in the unordered_multiset  <br> <span class="t-mark">(function template)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../container/queue/operator_cmp.html" title="cpp/container/queue/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span><span>operator&lt;</span><span>operator&lt;=</span><span>operator&gt;</span><span>operator&gt;=</span></span></a></div></div>
</td>
<td>   lexicographically compares the values in the queue  <br> <span class="t-mark">(function template)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../container/stack/operator_cmp.html" title="cpp/container/stack/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span><span>operator&lt;</span><span>operator&lt;=</span><span>operator&gt;</span><span>operator&gt;=</span></span></a></div></div>
</td>
<td>   lexicographically compares the values in the stack  <br> <span class="t-mark">(function template)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/reverse_iterator/operator_cmp.html" title="cpp/iterator/reverse iterator/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span><span>operator&lt;</span><span>operator&lt;=</span><span>operator&gt;</span><span>operator&gt;=</span></span></a></div></div>
</td>
<td>   compares the underlying iterators  <br> <span class="t-mark">(function template)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/move_iterator/operator_cmp.html" title="cpp/iterator/move iterator/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span><span>operator&lt;</span><span>operator&lt;=</span><span>operator&gt;</span><span>operator&gt;=</span></span></a></div></div>
</td>
<td>   compares the underlying iterators  <br> <span class="t-mark">(function template)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/istream_iterator/operator_cmp.html" title="cpp/iterator/istream iterator/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span></span></a></div></div>
</td>
<td>   compares two <code>istream_iterator</code>s  <br> <span class="t-mark">(function template)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/istreambuf_iterator/operator_cmp.html" title="cpp/iterator/istreambuf iterator/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span></span></a></div></div>
</td>
<td>   compares two <code>istreambuf_iterator</code>s  <br> <span class="t-mark">(function template)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../numeric/complex/operator_cmp.html" title="cpp/numeric/complex/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span></span></a></div></div>
</td>
<td>   compares two complex numbers or a complex and a scalar  <br> <span class="t-mark">(function template)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../numeric/valarray/operator_cmp.html" title="cpp/numeric/valarray/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span><span>operator&lt;</span><span>operator&lt;=</span><span>operator&gt;</span><span>operator&gt;=</span></span></a></div></div>
</td>
<td>   compares two valarrays or a valarray with a value  <br> <span class="t-mark">(function template)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../numeric/random/linear_congruential_engine/operator_cmp.html" title="cpp/numeric/random/linear congruential engine/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span></span></a></div></div>
</td>
<td>   compares the internal states of two pseudo-random number engines  <br> <span class="t-mark">(function)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../numeric/random/poisson_distribution/operator_cmp.html" title="cpp/numeric/random/poisson distribution/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span></span></a></div></div>
</td>
<td>    compares two distribution objects  <br> <span class="t-mark">(function)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../regex/sub_match/operator_cmp.html" title="cpp/regex/sub match/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span><span>operator&lt;</span><span>operator&lt;=</span><span>operator&gt;</span><span>operator&gt;=</span></span></a></div></div>
</td>
<td>   compares two <code>sub_match</code> objects  <br> <span class="t-mark">(function)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../regex/match_results/operator_cmp.html" title="cpp/regex/match results/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span></span></a></div></div>
</td>
<td>   lexicographically compares the values in the two match result  <br> <span class="t-mark">(function template)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../regex/regex_iterator/operator_cmp.html" title="cpp/regex/regex iterator/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span></span></a></div></div>
</td>
<td>   compares two <code>regex_iterator</code>s  <br> <span class="t-mark">(public member function of <code>std::regex_iterator</code>)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../regex/regex_token_iterator/operator_cmp.html" title="cpp/regex/regex token iterator/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span></span></a></div></div>
</td>
<td>   compares two <code>regex_token_iterator</code>s  <br> <span class="t-mark">(public member function of <code>std::regex_token_iterator</code>)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../thread/thread/id/operator_cmp.html" title="cpp/thread/thread/id/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span><span>operator&lt; </span><span> operator&lt;= </span><span> operator&gt; </span><span> operator&gt;=</span></span></a></div></div>
</td>
<td>   compares two <code>thread::id</code> objects <br> <span class="t-mark">(function)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../utility/rel_ops/operator_cmp.html" title="cpp/utility/rel ops/operator cmp"> <span class="t-lines"><span>operator!=</span><span>operator&gt;</span><span>operator&lt;=</span><span>operator&gt;=</span></span></a></div></div>
</td>
<td>   automatically generates comparison operators based on user-defined <span class="t-c"><span class="mw-geshi cpp source-cpp">operator<span class="sy1">==</span></span></span> and <span class="t-c"><span class="mw-geshi cpp source-cpp">operator<span class="sy1">&lt;</span></span></span>  <br> <span class="t-mark">(function template)</span> 
</td>
</tr>
</table>
<h3>
<span class="editsection">[<a href="http%3A//en.cppreference.com/mwiki/index.php" title="Edit section: See also">edit</a>]</span> <span class="mw-headline" id="See_also">See also</span>
</h3>
<p><a href="operator_precedence.html" title="cpp/language/operator precedence"> Operator precedence</a>
</p>
<table class="wikitable">

<tr style="text-align:center">
<th colspan="7"> Common operators
</th>
</tr>
<tr style="text-align:center">
<td> <a href="operator_assignment.html" title="cpp/language/operator assignment"> assignment</a>
</td>
<td> <a href="operator_incdec.html" title="cpp/language/operator incdec"> increment<br>decrement</a>
</td>
<td> <a href="operator_arithmetic.html" title="cpp/language/operator arithmetic"> arithmetic</a>
</td>
<td> <a href="operator_logical.html" title="cpp/language/operator logical"> logical</a>
</td>
<td> <strong class="selflink"> comparison</strong>
</td>
<td> <a href="operator_member_access.html" title="cpp/language/operator member access"> member<br>access</a>
</td>
<td> <a href="operator_other.html" title="cpp/language/operator other"> other</a>
</td>
</tr>
<tr style="text-align:center">
<td>
<p><span class="t-c"><span class="mw-geshi cpp source-cpp">a <span class="sy1">=</span> b<br>
a <span class="sy2">+</span><span class="sy1">=</span> b<br>
a <span class="sy2">-</span><span class="sy1">=</span> b<br>
a <span class="sy2">*</span><span class="sy1">=</span> b<br>
a <span class="sy2">/</span><span class="sy1">=</span> b<br>
a <span class="sy2">%</span><span class="sy1">=</span> b<br>
a <span class="sy3">&amp;</span><span class="sy1">=</span> b<br>
a <span class="sy3">|</span><span class="sy1">=</span> b<br>
a <span class="sy3">^</span><span class="sy1">=</span> b<br>
a <span class="sy1">&lt;&lt;=</span> b<br>
a <span class="sy1">&gt;&gt;=</span> b</span></span>
</p>
</td>
<td>
<p><span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy2">++</span>a<br>
<span class="sy2">--</span>a<br>
a<span class="sy2">++</span><br>
a<span class="sy2">--</span></span></span>
</p>
</td>
<td>
<p><span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy2">+</span>a<br>
<span class="sy2">-</span>a<br>
a <span class="sy2">+</span> b<br>
a <span class="sy2">-</span> b<br>
a <span class="sy2">*</span> b<br>
a <span class="sy2">/</span> b<br>
a <span class="sy2">%</span> b<br>
~a<br>
a <span class="sy3">&amp;</span> b<br>
a <span class="sy3">|</span> b<br>
a <span class="sy3">^</span> b<br>
a <span class="sy1">&lt;&lt;</span> b<br>
a <span class="sy1">&gt;&gt;</span> b</span></span>
</p>
</td>
<td>
<p><span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy3">!</span>a<br>
a <span class="sy3">&amp;&amp;</span> b<br>
a <span class="sy3">||</span> b</span></span>
</p>
</td>
<td>
<p><span class="t-c"><span class="mw-geshi cpp source-cpp">a <span class="sy1">==</span> b<br>
a <span class="sy3">!</span><span class="sy1">=</span> b<br>
a <span class="sy1">&lt;</span> b<br>
a <span class="sy1">&gt;</span> b<br>
a <span class="sy1">&lt;=</span> b<br>
a <span class="sy1">&gt;=</span> b</span></span>
</p>
</td>
<td>
<p><span class="t-c"><span class="mw-geshi cpp source-cpp">a<span class="br0">[</span>b<span class="br0">]</span><br>
<span class="sy2">*</span>a<br>
<span class="sy3">&amp;</span>a<br>
a<span class="sy2">-</span><span class="sy1">&gt;</span>b<br>
a.<span class="me1">b</span><br>
a<span class="sy2">-</span><span class="sy1">&gt;</span><span class="sy2">*</span>b<br>
a.<span class="sy2">*</span>b</span></span>
</p>
</td>
<td>
<p><span class="t-c"><span class="mw-geshi cpp source-cpp">a<span class="br0">(</span>...<span class="br0">)</span><br>
a, b<br>
<span class="br0">(</span>type<span class="br0">)</span> a<br>
<span class="sy4">?</span> <span class="sy4">:</span></span></span>
</p>
</td>
</tr>
<tr>
<th colspan="7"> Special operators
</th>
</tr>
<tr>
<td colspan="7">
<p><a href="static_cast.html" title="cpp/language/static cast"><tt>static_cast</tt></a> converts one type to another compatible type <br>
<a href="dynamic_cast.html" title="cpp/language/dynamic cast"><tt>dynamic_cast</tt></a> converts virtual base class to derived class<br>
<a href="const_cast.html" title="cpp/language/const cast"><tt>const_cast</tt></a> converts type to compatible type with different <a href="cv.html" title="cpp/language/cv">cv</a> qualifiers<br>
<a href="reinterpret_cast.html" title="cpp/language/reinterpret cast"><tt>reinterpret_cast</tt></a> converts type to incompatible type<br>
<a href="../memory/new/operator_new.html" title="cpp/memory/new/operator new"><tt>new</tt></a> allocates memory<br>
<a href="../memory/new/operator_delete.html" title="cpp/memory/new/operator delete"><tt>delete</tt></a> deallocates memory<br>
<a href="sizeof.html" title="cpp/language/sizeof"><tt>sizeof</tt></a> queries the size of a type<br>
<a href="sizeof....html" title="cpp/language/sizeof..."><tt>sizeof...</tt></a> queries the size of a <a href="parameter_pack.html" title="cpp/language/parameter pack">parameter pack</a> <span class="t-mark-rev t-since-cxx11">(since C++11)</span><br>
<a href="typeid.html" title="cpp/language/typeid"><tt>typeid</tt></a> queries the type information of a type<br>
<a href="noexcept.html" title="cpp/language/noexcept"><tt>noexcept</tt></a> checks if an expression can throw an exception <span class="t-mark-rev t-since-cxx11">(since C++11)</span><br>
<a href="alignof.html" title="cpp/language/alignof"><tt>alignof</tt></a> queries alignment requirements of a type <span class="t-mark-rev t-since-cxx11">(since C++11)</span>
</p>
</td>
</tr>
</table>

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